1. Field of the Invention
The present invention relates to a motor vehicle running condition monitoring and controlling system having two central processing units (CPUs) whose output signals are usually compared with each other to confirm a running condition monitoring operation, and which are used as controlling and monitoring CPUs, respectively, for effecting and monitoring a certain vehicle controlling operation such as a brake controlling operation.
2. Description of the Related Art
Motor vehicle running condition monitoring systems for use with motor vehicles such as motorcycles, for example, determine an estimated vehicle speed, an estimated vehicle deceleration, wheel acceleration and deceleration, and a slip rate from a wheel speed detected by a vehicle speed sensor for monitoring a motor vehicle running condition. The motor vehicle running condition monitoring systems have two CPUs for carrying out the same operation, and the two CPUs produce output signals that are compared with each other to check their operation for errors.
The output signals from the two CPUs are always compared with each other only for the purpose of confirming the monitoring operation. Another controlling function, such as a brake controlling operation, that needs a shorter loop time than the loop time for monitoring a motor vehicle running condition is required to be carried out by another CPU than those for monitoring the motor vehicle running condition. Therefore, the number of CPUs installed on the motor vehicle is increased. Such a motor vehicle running condition monitoring system is disclosed in Japanese laid-open patent publication No. 3-217364, for example.